"We joined the mujahideen against you!" Malang says he told his dumbfounded Taliban chief, Commander Habib, who pleaded with the soldiers to stay.

"It's finished," Malang says he replied with relish. "We are already with them." The swap-over of Malang's unit is another chink in the armor of the Taliban, which has been subject to an increasing number of defections to the Northern Alliance - some estimate several thousand - since American airstrikes began against Taliban strongholds on Oct. 7.

Some are already proving militarily significant. One mass defection of 1,000 Taliban fighters last week cut off the Taliban's main supply route to the northern city of Mazar-e Sharif. The Pentagon confirmed Wednesday that rebels were advancing on the strategic airport there, as US aircraft reportedly assisted by blasting Taliban positions and tank concentrations.

Alliance officials also speak of another 4,000 defectors in one mass defection - adding territory under their control to the Alliance.

These former Taliban fighters describe growing discontent among Taliban ranks. But the reports of defections also underscore a critical - if uncommon - element of waging war here: The decision to defect is often more political than military, an act that is made without shame, to minimize war deaths and save families and villages.

For example, when the Taliban mullahs swept up through Afghanistan in the mid-1990s, taking control of more than 90 percent of the country, they did so by buying off local commanders of the mujahideen - an assortment of Islamic groups that had spent a decade fighting the Soviets. Firing a shot was rare; waging pitched battles even more rare. Defections from the mujahideen back then tilted the balance.

Today the wind is blowing the other way, as US airstrikes signal to wavering Taliban soldiers that they are on the losing side, and should join the rebels if they want to survive.

"We joined the mujahideen [Northern Alliance] because the Taliban are going to withdraw, and will disappear in the near future," says Khan Mohamed, a father of two, who defected from the Taliban with Malang. "From the time the US attacks began, day by day the Taliban are becoming weaker."

Sniffing the wind four years ago, as the Taliban moved north, Mr. Mohamed's unit defected from the mujahideen to the Taliban, because there was "no way to bring food" to their village of Shukhi if they resisted, he says. And because "we had no choice."

"These defectors are not the highly religious Taliban [stalwarts]," says Alliance General Babajan, who controls the Bagram front 25 miles north of Kabul, and tallies the number of defectors at 7,000 to 8,000 since US airstrikes began. "They were mujahideen before, so they can come here. We know them.

"This is a big success for us, and can be a big reason for the collapse of the Taliban," General Babajan says. Areas in north and west Afghanistan could easily fall this way, he adds, if the wave of defections grows. But there are limits, too.

"In Taliban strongholds in the south, where there are also terrorists, then we will have to fight against them," Babajan says. Until then, alliance territory may grow and grow, with little actual fighting.

Malang and his unit of defectors say their grievances against the Taliban are many. The dwarfish commander, who fought the Soviet occupation for a decade in the 1980s, says he has been in touch secretly with the rebels by radio for five years.

"Now our [Taliban] commander is angry, and he is afraid that other strongholds might go," says Malang, holding his weathered radio in front of him. Once a tool for coordinating strikes against the alliance, it became the instrument of his unit's liberation on Wednesday. "That's a big problem for our commander. There are lots of Taliban ready to come over."

Besides the pressure due to US airstrikes, these defectors say they have grown increasingly disillusioned with Taliban policies - especially that of relying on non-Afghan, Arab fighters loyal to bin Laden in their campaigns.

"People are now becoming aware that the ruling Taliban is wrong, that they misuse the name of Islam," says Mohamed, sitting on his haunches and holding the barrel of his Kalashnikov in the tower of an Alliance base. "The Pakistani, Arab, and Chechen troops came here to rule. This is the main reason for Taliban fighters to join the mujahideen."

His troops are all members of Afghanistan's dominant ethnic Pashtuns, who make up the bedrock of ethnic support for the Taliban. The Northern Alliance, by contrast, is a loose grouping of ethnic minorities, such as Tajiks, Uzbeks, and Shiite Muslim Hazaras.

And they say there is absolutely no shame attached to switching allegiances, and are not worried about treason as a grave crime as it is in other war zones

"No, it's not a shame," Mohamed says, and his former Taliban fighters nod in agreement. "Because we know that the Taliban are treacherous. I have seen them by my own eyes."

But can this war be won by defections alone, such as the one Malang orchestrated with his walkie-talkie?